Combined electric and magnetic deflecting system for cathode ray tubes



June 7, 1938. RUSKA A 2,119,795 COMBINED ELECTRIC AND MAGNETIC DEFLECTING SYSTEM FOR OATHODE RAY TUBES Filed June 6, 1936 I I l I 1 1 1 I I I,

. 20 heating. When the electrodes are positioned is either fitted into the inner tube l2 or onto the 20 Patented June 7, 1938 I COMBINED ELECTRIC AND MAGNETIC DE FLECTING SYSTEM FOR CATHODE RAY TUBES Ernst Ruska and Erich Schwartz, Berlin-Zehlendorf, Germany, assignors to the firm of. Fernsch Aktiengesellschaft, Zehlendorf, near Berlin, Germany Application June 6, 1936, Serial No. 83,978 In Germany June 19, 1935 4 Claims. (01. 250-275) The present invention relates to the construcsize that the maximum outwardly deflected ray tion of the cross deflecting systems used in cathcan just leave the plate without touching. 'In

One object of the invention is to provide a pl es he an e potential in the ease f ym-- deflecting system which is characterized by its metrically biased p 7 19 particular simplicity and compact structure and The retaining yoke 4 of the deflecting system 10 which at the same time may be produced by the ay be p v ed a t ray inlet d a o glass blowing art. It has hitherto been customentric to the passage portion of the ray, with a ary to fasten the individual electrodes to fused-in conical or cap shaped fitting surface 8 by means tips or to arrange them in order on glass or of which the system can be centered on correceramic supports. Difiiculties arise however when sponding surfaces H) of the glass base said fitting 15 a large number of electrodes is used since the surface 8 having a flat base l8 fixed to yoke 4. position of the individual electrodes cannot be The glass base consists of two concentric tubes maintained with sufiicient accuracy during their l2 and I3 which are fused together on the side n u onal positioning and after pr l minary turned towards the screen. The conical portion with insulating elements interposed between them outer tube l3 and its base plate l8 suspended by the inexactness of adjustment increases as the means not illustrated, at three points on its peseparation from the first electrode forming the ripher e, g, y means of wire loops and screws, reference surface increases, so that the last electo three hooks or lugs on the outermost base trodes embody unpermissible positional errors. tube. Spreading springs M, e. g. four springs 25 In accordance with the present invention two made of nickel-beryllium alloy may be fastened deflecting plates are fastened to a common supto the base plate I 8 so as to effect contact of the port by means of the insulating coil members used conducting inner wall l5 which engages yoke 4' for both defle ing win in h s id s pport and is concentric with tubes l2 and is with an serving to hold both halves of the deflecting sysinternal metal or high-ohmic coating l9 serving 30 tem in a rigid manner facing each other. subsequently to accelerate the already crosscon' The draw illustrates y y of embodiment trolled cathode ray. The lead-in conductors [6 a tube in which the common suppo member is leading to the deflecting plates and coils as well positionally adjusted through agency o a fi n as those carrying the anode voltage. arepre'ferably surface of the glass wall of the tube. located at the fusion junction of both base tubes. 35 1 shows a section through a portion of t A small ray-concentrating collector coil, not base of the tube. shown, may be disposed in the concentric annu- 40 coordinate direction, are W u n two nsulatin Wards the screen-side end of the coil, the coil 40 coil bodies 2 which a e coa a y a y being surrounded by an iron jacket open at that axially disposed close to both sides of the ray and d, I upon the mutually facing sides of which the two Wh t is i d electrically deflecting plates 3 are fastened. The 1, In a cathode ray tube, deflecting electrode l5 co ls a connected on h other side y means of mounting means comprising a reentrantly folded a connecting member or yoke 4. This yoke per annular envelope portion, a conical supporting se serves to eifect the entire adjustment of the and conducting element adapted to inwardly ensystem. In the arrangement shown in Fig. 1 the gage said annular envelope portion, a bi-furcated ray passes through the center of the yoke and. yoke fixed to said conical element, a spool of o enters into the system. For this purpose the insulating material fixed to each bi-furcated yoke 4 is provided at that point with an opening portion of said yoke, a deflecting coil wound about 5 which is centered with respect to the system. each of said spools, and a deflecting plate fixed The plates 3 are suitably adapted to accommodate upon each of said spools. the ray, that is, they have an inlet interval equal 2. In a cathode ray tube having an envelope 5 to the ray diameter and an outlet interval of such enclosing electrodes, electrode mounting means,

2 comprising a doubly reentrant annular stem portion formed in said envelope, a bi-furcated yoke having divergent legs, a conical apertured member disposed centrally upon said yoke, an insulating spool disposed adjacently upon each yoke leg, as deflecting coil wound about each of said spools, and a deflecting plate disposed upon each of said spools; said conical member being adapted to fit within said annular stem portion, and having means formed on said envelope wall adapted to cooperate therewith to fixedly constrain said conical member.

3. In a cathode ray tube as described in claim 2, field controlling means comprising plates fixed to each of said spools in approximate continuance of and divergent from said deflecting plates.

4. In a cathode ray tube having deflecting means supported therein after claim 2, having a conducting coating disposed inwardly upon the tube walls, means for connecting said supporting yoke to said conducting wall coating.

ERICH SCHWARTZ. ERNST RUSKA. 

